Prosthetic ankle module

ABSTRACT

A prosthetic ankle module allows for translational and/or rotational movement of a prosthetic foot relative to an adapter. The ankle module can include a four-bar linkage assembly. Links of the linkage assembly can be arranged in various configurations, e.g., parallel or non-parallel and having equal or non-equal lengths, to provide different functions and benefits, e.g., dorsiflexion, plantar flexion, vertical shock absorption, inversion, eversion, and/or rotation about the sagittal axis. Other types of linkage assemblies are also possible. A prosthetic foot can further include a support spring to limit the range of motion of the adapter in use.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 13/955,988, filed Jul. 31, 2013, which claims priority benefitunder 35 U.S.C. § 119(e) as a nonprovisional of U.S. ProvisionalApplication No. 61/678,493, filed Aug. 1, 2012, each of which is herebyincorporated by reference herein in each entirety and should beconsidered a part of this specification.

BACKGROUND

Field

The present application relates to prosthetics in general, and moreparticularly, to prosthetic feet having a prosthetic ankle module and/orsupport spring.

Description of the Related Art

Various types of prosthetic devices are available as substitutes forhuman limbs and joints. Many prosthetic devices available todayincorporate various features to try to better approximate thefunctioning of natural limbs and joints. For example, some prostheticfoot designs seek to provide improved foot rollover, ankle function, andenergy storage and return during use.

Prosthetic feet are often attached to a user's residual limb or otherprosthetic components (e.g., a pylon) via adapters that may be bolted,glued, or otherwise coupled directly to the foot. Conventional adapterscan allow for relative adjustment between prosthetic components duringalignment, but typically fix the components relative to each otherduring use.

SUMMARY

A prosthetic ankle module according to the present disclosure isconfigured to couple a prosthetic foot to an adapter, which in turn isconfigured to be coupled to a user's residual limb or another prostheticcomponent, such as a pylon. The ankle module allows for relativemovement (i.e., translation and/or rotation) between the foot andadapter during ambulation, which results in improved rolloverperformance of the foot. A prosthetic foot according to the presentdisclosure can also include a support spring to help limit the range ofmotion of the adapter during use and provide additional shock absorptionduring ambulation.

In some embodiments, a prosthetic foot assembly includes an elongatefoot member, an adapter assembly, and an ankle module. The elongate footmember has a generally vertical attachment portion at a proximal end,and the adapter assembly is configured to be coupled to anotherprosthetic component, such as a socket or pylon. The ankle modulecouples the attachment portion of the foot member to the adapterassembly via two or more joints and allows translational and/or pivotalmovement of the foot member relative to the adapter assembly via thejoints.

In some embodiments, a prosthetic foot assembly includes an elongatefoot member, an adapter assembly, and one or more linkages. The elongatefoot member has a generally vertical attachment portion at a proximalend. The adapter assembly is configured to be coupled to anotherprosthetic component, such as a socket or pylon. In some embodiments,the adapter assembly is horizontally spaced from the generally verticalattachment portion of the foot member. The attachment portion isconfigured to move relative to the adapter assembly during ambulation ofthe prosthetic foot. The linkages extend between and pivotally couplethe vertical attachment portion and adapter assembly to allow the footmember to pivotally move relative to the adapter portion duringambulation. In some embodiments, the linkages facilitate plantarflexionof the foot upon heel strike.

In some embodiments, a prosthetic foot assembly includes an adapterassembly, an elongate foot member, and a linkage assembly. The adapterassembly is configured to be coupled to another prosthetic component,such as a socket or pylon, and includes two or more joints. A proximalend of the elongate foot member includes a generally vertical attachmentportion that includes two or more joints and is horizontally spaced fromthe adapter assembly. The linkage assembly couples and allows relativemovement between the foot member and the adapter assembly. The linkageassembly includes an upper link and a lower link on both a medial and alateral side of the foot member and adapter assembly. The links extendbetween the joints of the adapter assembly and foot member. In someembodiments, the upper links have different lengths than the lower linksand the upper links and lower links are not parallel.

For purposes of summarizing the disclosure and the advantages achievedover the prior art, certain objects and advantages are described herein.Of course, it is to be understood that not necessarily all such objectsor advantages need to be achieved in accordance with any particularembodiment. Thus, for example, those skilled in the art will recognizethat the disclosure may be embodied or carried out in a manner thatachieves or optimizes one advantage or group of advantages as taught orsuggested herein without necessarily achieving other objects oradvantages as may be taught or suggested herein.

All of these embodiments are intended to be within the scope of thedisclosure herein. These and other embodiments will become readilyapparent to those skilled in the art from the following detaileddescription having reference to the attached figures, the disclosure notbeing limited to any particular disclosed embodiment(s).

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of the presentdisclosure are described with reference to the drawings of certainembodiments, which are intended to schematically illustrate certainembodiments and not to limit the disclosure.

FIG. 1A schematically illustrates an example embodiment of a footassembly having an ankle module and support spring;

FIGS. 1B and 1C schematically illustrate the foot assembly of FIG. 1A ina cosmesis cover;

FIGS. 2A-2B schematically illustrate exploded views of the foot assemblyof FIG. 1A;

FIG. 2C schematically illustrates links of the foot assembly of FIG. 1A;

FIGS. 2D-2F schematically illustrate a connection sleeve of the footassembly of FIG. 1A;

FIG. 2G schematically illustrates the connection sleeve of FIGS. 2D-2Fcoupled to a prosthetic foot;

FIGS. 2H-2I schematically illustrate another embodiment of a connectionsleeve;

FIG. 2J schematically illustrates the connection sleeve of FIGS. 2H-2Icoupled to a prosthetic foot;

FIG. 2K schematically illustrates a support spring of the foot assemblyof FIG. 1A;

FIG. 2L schematically illustrates the foot assembly of FIG. 1A includingfoam coupling the support spring to the foot;

FIG. 2M schematically illustrates an example embodiment of a footassembly having an ankle module;

FIGS. 3A-3F schematically illustrates hypothetical linkage assemblyarrangements and the application of three different ground reactionforces to the feet;

FIGS. 4A-4I schematically illustrate example embodiments of four-barlinkage assemblies;

FIGS. 4J-4K schematically illustrate a prosthetic foot assembly having alinkage that allows for plantarflexion when loaded;

FIG. 4L illustrates a graph showing toe position of the foot of FIG. 4Hand of the sound leg during the gait cycle;

FIG. 4M illustrates a graph showing toe position of the foot of FIG. 4Fand of the sound leg during the gait cycle;

FIGS. 5A-6B schematically illustrate linkage assemblies allowing forthree-dimensional motion;

FIGS. 7A and 7B schematically illustrate an alternative link embodiment;

FIGS. 8-13 schematically illustrate other embodiments of linkageassemblies;

FIGS. 14A and 14B schematically illustrate the effect of differentcenters of rotation on compression of a support spring;

FIGS. 15A-16B schematically illustrate linkage assemblies formed by afoot and/or heel member;

FIGS. 17A and 17B schematically illustrate prosthetic feet assemblieshaving mechanisms to provide toe clearance during swing;

FIGS. 18A and 18B illustrate adapters allowing for heel height and/orleg length adjustment;

FIGS. 19A-19C schematically illustrate an example embodiment of aprosthetic foot assembly;

FIG. 20 schematically illustrates an example embodiment of a prostheticfoot and linkage assembly for simulating knee flexion;

FIG. 21A schematically illustrates a schematic of a linkage assembly forsimulating knee flexion during early stance;

FIG. 21B schematically illustrates the linkage assembly of FIG. 21Aduring full stance.

DETAILED DESCRIPTION

Although certain embodiments and examples are described below, those ofskill in the art will appreciate that the disclosure extends beyond thespecifically disclosed embodiments and/or uses and obvious modificationsand equivalents thereof. Thus, it is intended that the scope of thedisclosure herein disclosed should not be limited by any particularembodiments described below.

A prosthetic ankle module as described herein can include one or morejoints associated with a prosthetic foot and connected to one or morejoints associated with an adapter. In one embodiment, the joints arepivot points that allow for rotation of one component relative toanother. The joints allow the foot to move relative to the adapterduring ambulation. For example, the joints can allow the foot to movetranslationally and/or rotationally relative to the adapter about atleast two joints (e.g., pivot points). In some embodiments, theprosthetic foot is coupled to the adapter via a linkage assemblyincluding one or more links extending generally horizontally between thejoints on the foot and adapter. The joints and links can be provided invarious configurations allowing the ankle module to perform differentfunctions, for example, dorsiflexion, plantar flexion, and/or shockabsorption at various stages of the user's gait cycle. In someembodiments, the ankle module further includes a support springextending between the adapter and foot to limit the range of motion ofthe adapter during use, provide additional shock absorption, and improveenergy storage and return.

In some embodiments, such as the example embodiment illustrated in FIG.1A, the ankle module 300 includes two joints 310 on each of the medialand lateral sides of both the foot 100 and adapter 200, for a total ofeight joints. The linkage assembly coupling the foot to the adapterincludes a four bar linkage having two bars or links on each of themedial and lateral sides of the ankle. In one embodiment, the links canbe pivotably coupled to the foot and adapter at the joints, allowingrelative movement between the foot and adapter during ambulation. Inanother embodiment, the links are not pivotably coupled to the footand/or adapter, but flex to allow for relative motion between the footand adapter.

The example prosthetic foot assembly shown in FIG. 1A and the explodedviews of FIGS. 2A and 2B includes a prosthetic foot 100, a connectionsleeve 320, an adapter 200, two top links 330, two bottom links 340, anda support spring 400. In the illustrated embodiment, the foot 100includes a foot member 110 extending from a generallyvertically-oriented attachment section 112 downwards and forwards to adistal toe end 114 and a heel member 120 extending from a distal end 124rearwardly to a free, cantilevered proximal heel end 122. A portion ofthe heel member 120 proximate the distal end 124 is coupled to the footmember 110 between the attachment section 112 and toe end 114. However,other types of prosthetic feet can also be used with the ankle moduledescribed herein.

The illustrated adapter 200 includes a generally vertical elongate body210 and a connector, such as a male pyramid 220, configured to becoupled to a corresponding connector of a prosthetic socket or anotherprosthetic component, such as a pylon. However, the adapter 200 can haveother configurations and include types of connectors other than a malepyramid. The adapter 200 also includes two bores 230 extending generallyhorizontally through the adapter 200. The top 330 and bottom 340 links,illustrated in FIG. 2C, are generally elongate bars having an apertureproximate each end. In some embodiments, the apertures have diameters ofabout 12.8 mm. The links 330, 340 can have the same or varying lengthsand configurations. In some embodiments, the links are selected and/ordesigned to be able to withstand forces of up to about 1.31*10⁴ N inuse. In some embodiments, the links are made of carbon fiber. However,the links can be made of other suitable materials and designed towithstand forces higher than noted above.

As illustrated in FIGS. 2D-2F, the connection sleeve 320 includes aninterior cavity 324 configured to receive the attachment section 112 ofthe foot member 110. The connection sleeve 320 also includes two bores322 extending generally horizontally through the connection sleeve 320.In some embodiments, the connection sleeve 320 is made of aluminum.However, other suitable materials can be used. FIG. 2E is across-sectional view of the connection sleeve 320 along a coronal orfrontal plane, and FIG. 2F is a cross-sectional view of the connectionsleeve 320 along a sagittal plane.

To assemble the ankle module 300, the connection sleeve 320 is placed onthe attachment section 112 of the prosthetic foot 100 as shown in FIG.2G. In some embodiments, screws are inserted into apertures 326 tosecure the connection sleeve 320 to the foot member 110. Additionally oralternatively, glue or another adhesive can be introduced into thecavity 324 via aperture 328 to secure the connection sleeve 320 to thefoot member 110. An aperture 327 in a top surface of the connectionsleeve 320 can allow for air to escape the cavity 324 as glue or anotheradhesive is introduced into the cavity 324.

FIGS. 2H-2J illustrate an alternative embodiment of a connection sleeve320. In this embodiment, the connection sleeve 320 is integrated withthe attachment portion 112 of the foot member 110. This connectionsleeve 320 can be integrally (e.g., monolithically) formed with theattachment portion 112 or glued onto the attachment portion 112. Theconnection sleeve 320 can further include a vertical slot 323. Thisalternative connection sleeve 320 can advantageously be smaller and/orlighter.

The links 330, 340 are arranged so that each link extends between theconnection sleeve 320 and the adapter 200 and the apertures in the links330, 340 are aligned with the bores 322, 230 through the connectionsleeve 320 and adapter 200, respectively. In some embodiments having thealternative connection sleeve of FIGS. 2H-2J, the linkage assembly caninclude a single bottom link 340 that extends through the slot 323 toalign with the connection sleeve 320 bore 322. The links 330, 340 arecoupled to the connection sleeve 320 and adapter 200 via pins 350. Eachpin 350 extends through an aperture in a link 330, 340, a bore 230, 322in the adapter 200 or connection sleeve 320, respectively, and anaperture in another link 330, 340. Bushings 352 and washers 354 can alsobe placed along the pins 350 to help protect the link apertures and pins350 from wear and create the joints 310 that allow for pivotal movementof the links 330, 340, as shown in the illustrated embodiment. In someembodiments, pin roller bearings are used instead of bushings to provideimproved wear resistance.

In some embodiments, an ankle module 300 can be used with other types ofprosthetic feet, for example, prosthetic foot 101 shown in the exampleembodiment illustrated in FIG. 2M. As shown, prosthetic foot 101includes a foot member 111 extending from a proximal heel end 122 to adistal toe end 114. In the illustrated embodiment, the connection sleeve320 includes a base 321, so that the connection sleeve 320 and base 321are one piece. In another embodiment, the connection sleeve 320 and base321 can be separate components coupled to each other. When theprosthetic foot 101 is assembled, the base 321 of the connection sleeve320 is placed on a block 421, which is placed on a top surface of thefoot member 111. The block 421 can be of a resilient material (e.g.,foam). The block 421 can advantageously allow for multi-axial movementof the foot during use. In some embodiments, the base 321 and block 421and/or the block 421 and foot member 111 are coupled with an adhesive,e.g., glue. Additionally or alternatively, the base 321, block 421, andfoot member 111 can be secured with one or more straps 130 extendingaround a top of the base 321 and bottom of the foot member 111 as shownin FIG. 2M. In some such embodiments, the straps 130 can be made of anelastic material to allow for flexion of the prosthetic foot 101 duringuse. The example prosthetic foot 101 of FIG. 2M can advantageously beappropriate for low-activity users. Such users may require or preferstability and/or comfort over high performance and/or energy return, butmay still benefit from various features the ankle module 300 canprovide, for example, dorsiflexion, plantar flexion, and/or shockabsorption at various stages of the user's gait cycle. In someembodiments, the prosthetic foot 101 also includes a spring 401extending between the base 321 of the coupling sleeve 320 and theadapter 200. Instead of or in addition to the spring 401, the foot 101can include a damper (e.g., hydraulic damper) between the base 321 andthe adapter 200. The spring 401 and/or damper can help limit and/orcontrol movement or the adapter 200 to provide a less dynamic and/ormore stable foot for low activity users. Advantageously, the foot 101dorsiflexes at toe-off for toe clearance during the swing phase of gait.

In use, the adapter is fixed relative to the user, and the foottranslates and/or rotates (e.g., moves along an arcuate path disposed ona circle aligned with a longitudinal axis of the foot) relative to theadapter during ambulation. The movement of the foot about the adapter isbased on the location of a ground reaction force applied to the footduring ambulation relative to an instantaneous center of rotation forthe foot. The location of the foot's instantaneous center of rotationdepends on the particular characteristics and arrangement of the linksin the linkage assembly. In some embodiments, the center of rotation islocated at a point where lines projected in either direction from theends of the top and bottom links cross. In use, the instantaneous centerof rotation can change as the user progresses through the stages of thegait cycle because as the foot moves relative to the adapter, the linkspivot at the joints on the foot and adapter and the orientation of thetop and bottom links relative to each other can change. As the crossingpoint and therefore the center of rotation move farther away from thefoot, the arc of rotation of the foot about the adapter flattens,resulting in more translational movement and less rotational movement.If the center of rotation is infinitely far away from the foot, forexample, if the top and bottom links are parallel and of equal length,the foot may only translate and not rotate relative to the adapter.

FIG. 3 illustrates two hypothetical linkage assembly arrangements andthe results of application of three different ground reaction forces tothe feet. The dots represent the instantaneous center of rotation, thestraight arrows and dashed lines show the ground reaction forces duringdifferent stages of the stance phase of the gait cycle, and the curvedarrows near the dots illustrate the direction of rotation of the footabout the center of rotation. The linkage assembly arrangement of A-Ccauses the center of rotation to be in front of the foot, whereas thecenter of rotation is behind the foot with the linkage assemblyarrangement of D-F. A and D show the ground reaction forces at heelstrike, B and E show the forces and mid-stance, and C and F show theforces at toe off. The ground reaction forces in A, B, and D are behindthe center of rotation, causing a clockwise rotation and plantarflexionof the foot. The ground reaction forces in C, E, and F are in front ofthe center of rotation, causing a counterclockwise rotation and dorsalflexion of the foot.

Varying the number, length, and/or orientation of the links 330, 340 cantherefore cause the ankle module 300 and foot 100 to act differently andprovide different benefits in various stages of the gait cycle. In theexample embodiment illustrated in FIG. 1A, the upper 330 and lower 340links have different lengths and are orientated non-parallel to eachother. This configuration can promote dorsiflexion through mid-stanceand plantar flexion at toe off. In various embodiments, the links 330,340 can be selected and arranged to achieve certain desired functionsand advantages such as: plantar and/or dorsal flexion, for example,dorsiflexion during stance and/or plantarflexion at toe off, verticalshock absorption, rotation of the foot in the transverse (horizontal)plane or about the sagittal axis, inversion and/or eversion, toeclearance during the swing phase of the gait cycle, for example, viadorsiflexion during swing, and/or heel height adjustment. For example,the foot 101 illustrated in FIG. 2M can provide dorsiflexion upontoe-off to allow for toe clearance during swing for low active users.

Linkage Assemblies

FIGS. 4A-4I illustrate schematics and example embodiments of variouspossible linkage assembly arrangements. Of course these are only examplearrangements, and others are also possible. Furthermore, althoughcertain functions are described for each arrangement, other functionsmay result from a particular arrangement in addition to or instead ofthe functions described, for example, depending on the actual lengths,arrangements, angles, and other characteristics of the links selectedfor a given implementation of these concepts.

In the arrangement of FIG. 4A, the top links T and bottom links B areparallel and have equal lengths. The instantaneous center of rotation istherefore at infinity, so the foot translates but does not significantlyrotate about the adapter. This arrangement advantageously providesvertical shock absorption when the foot is loaded and vertical motionback to neutral upon unloading. The top T and bottom B links areparallel in the arrangements of FIGS. 4B and 4C as well. However, in thearrangement of FIG. 4B, the top links T are longer than the bottom linksB, and in the arrangement of FIG. 4C, the top links T are shorter thanthe bottom links B. Due to the parallel orientation of the links, thecenter of rotation is at infinity so the foot translates but does notrotate upon initial loading, providing vertical shock absorption in botharrangements. In some embodiments having shorter bottom links B as inthe arrangement of FIG. 4B, the foot has a center of rotation behind thefoot during stance, causing dorsiflexion. Dorsiflexion during stance canadvantageously provide the user with more freedom on the foot, as thedorsiflexion helps stiffen the foot providing stability and helpingprevent the user from falling. During unloading, the foot mayplantarflex then provide vertical motion back to neutral. The footassembly embodiment 100B shown on the right of FIG. 4B also includes abumper 360 located within the linkage assembly. The bumper 360 can bemade of a resilient material (e.g., rubber) and can advantageously helpstiffen the foot during at least a portion of gait (e.g., duringdorsiflexion). In some embodiments having shorter top links T as in thearrangement of FIG. 4C, the center of rotation is in front of the footduring stance, causing plantarflexion. During unloading, the foot maydorsiflex then provide vertical motion back to neutral. Dorsiflexionupon unloading prior to the swing phase can also advantageously providetoe clearance during swing. However, because the top T and bottom Blinks are parallel, the center of rotation may be distant from the foot,resulting in greater translational and less rotational movement.

In the example arrangements of FIGS. 4D-4I, the top links T and bottomlinks B are non-parallel to each other. This often allows for greaterrotational motion compared to arrangements having parallel top andbottom links. In the arrangement of FIG. 4D, the top T and bottom Blinks have substantially equal lengths. The front or distal ends of thetop T and bottom B links are angled toward one another, so the center ofrotation is in front of the foot. The foot therefore plantarflexes uponloading and during stance, then dorsiflexes during toe off and uponunloading. As mentioned above, dorsiflexion during pre-swing canadvantageously provide for toe clearance during swing. Furthermore, witha linkage arrangement that produces plantarflexion when loaded, the footcan be aligned so that it is slightly dorsiflexed when unloaded to allowfor improved toe clearance during swing, for example as shown in FIGS.4J-4K. With such an alignment, the foot can plantarflex to a desiredalignment upon heel contact and then advantageously dorsiflex back toits unloaded alignment at toe off to provide the toe clearance duringthe swing phase of the gait cycle. In the arrangement of FIG. 4E, thetop T and bottom B links also have substantially equal lengths, but therear or proximal ends of the links are angled toward one another, so thecenter of rotation is behind the foot. In some embodiments, a foothaving such an arrangement may dorsiflex upon loading and during stanceand plantarflex during unloading.

In example arrangements of FIGS. 4F-4I, the top links T and bottom linksB have un-equal lengths. In the arrangements of FIG. 4F, the bottom linkB is shorter than the top link T, and the center of rotation is on thefoot. During loading the center of rotation is in front of the groundreaction force, producing plantar flexion. In some embodiments, thisarrangement provides vertical shock absorption during mid-stance andvertical motion back to neutral and dorsiflexion on unloading, which canprovide toe clearance in swing. For example, at a point about 80% intothe user's gait cycle (during swing), the toe might clear the ground bya vertical distance of about 15 mm more than an alternative foot, forexample, a foot such as the example embodiment shown in FIG. 4H. FIG. 4Lillustrates a graph showing the vertical position of a marker on the toeof the foot of FIG. 4H over the course of the gait cycle compared to thevertical position of a marker on the toe of the sound leg. FIG. 4Millustrates a graph of the vertical position of the toe of the foot ofFIG. 4F compared to the sound leg. In these graphs, toe-off occurs at apoint about 65% into the step. This is the lowest point of the graphbecause the marker rotates over the toe toward the ground duringtoe-off. The following peak occurs when the foot is behind the user'sbody, and the foot passes through the center to move in front of thebody at about 80%. The point at which the foot passes through center(about 80%) is important as it is the point during swing at which thefoot and toe come closest to the ground and ensuring toe clearance ismost needed. The vertical shock can result from movement of the foot andankle assembly that causes the top and bottom links to become closer toparallel. In some embodiments however, the foot dorsiflexes duringstance then again plantar flexes upon unloading. Dorsiflexion duringstance can help a user move over the foot more easily during ambulationand provide a smoother or improved rollover. This can be the result ofless motion of the links so that they remain non-parallel, which can beaccomplished by a stiffer foot and/or support spring. Plantar flexionduring toe off and unloading can advantageously provide an improved pushoff and a softer toe feel for users. Plantar flexion can be achieved ifthe ground reaction force crosses the instantaneous point of rotationduring ambulation. The foot assembly embodiment 100Fa shown in thecenter of FIG. 4F also includes a bumper 360 located within the linkageassembly. The bumper 360 advantageously helps inhibit excess dorsalflexion of the foot, similar to the stiffening of an able-bodied gaitduring ambulation. In the arrangement of FIG. 4G, the center of rotationcan be behind the foot, resulting in dorsiflexion during loading amid-stance and plantarflexion during unloading. In the arrangement ofFIG. 4H, the center of rotation can again be behind the foot, providingdorsiflexion during loading and plantar flexion during unloading.Depending on the distance of the center of rotation from the foot,during certain phase of the gait cycle, such as mid-stance and terminalstance, the center of rotation may approach infinity, providing verticalshock absorption and vertical motion back to neutral during thosephases. In the example embodiment 100Hb shown on the right of FIG. 4H,the center of rotation starts close behind the foot, allowing for slightplantar flexion at heel strike, and shifts farther away from the footduring stance. As the center of rotation moves farther away, the footrotates less and translates more, allowing for dorsiflexion duringloading followed by progressive stiffening of the foot through stance.In some embodiments, this linkage arrangement allows for dorsal flexionof up to about 10-15° and about 10 mm of vertical motion. In someembodiments, the arrangement of FIG. 4H provides push off at toe off andmay provide greater push off than, for example, the arrangement of FIG.4F. In the arrangement of FIG. 4I, the center of rotation is in front ofthe foot, providing plantar flexion during loading and midstance, anddorsiflexion during unloading.

Three-Dimensional Motion

In some embodiments, the ankle module 300 can be configured to allow forthree-dimensional motion in and about different anatomical planes andaxes during ambulation. For example, in some embodiments, the anklemodule 300 includes three links, e.g., two top links 330 and one bottomlink 340 as shown in FIGS. 5A and 5B or one top link and two bottomlinks. In the illustrated embodiment, the top 330 and bottom 340 linksare parallel. However, the configurations illustrated in FIGS. 4A-4I anddescribed herein or other arrangements are also possible. In someembodiments, a link or links on the medial side of the ankle can bealigned along a different axis than a link or links on the lateral sideof the ankle (i.e., links on the medial and lateral sides can benon-parallel in the sagittal plane). Links on the medial and lateralsides of the ankle can have the same or different lengths. In someembodiments, the links are flexible. These features can allow theadapter 200 to rotate clockwise or counterclockwise in the transverseplane during ambulation. For example, a longer link on the medial sideof the foot can cause clockwise rotation of the adapter 200 (e.g.,rotation in a clockwise direction when viewed from the front of theprosthetic foot). In some embodiments, this rotation can help guide thefoot in a medial to lateral or lateral to medial direction duringambulation to help produce a smoother and more natural rollover.

In some embodiments, the ankle module 300 includes four links and thetwo links on one side (medial or lateral) of the ankle are shorter thanthe two links on the other side. This can produce inversion or eversionof the adapter 200 (rotation of the adapter 200 about the coronal axis)during ambulation. In some embodiments, for example as shown in FIGS. 6Aand 6B, links on the medial and lateral sides are offset from or alignedat an angle to one another when viewed from the front or back. Thiscauses movement of the adapter 200 in the medial or lateral direction(movement in the coronal plane or movement into or out of the sagittalplane) during ambulation. In some embodiments, the links havespring-like properties, allowing movement of the adapter 200 in thesagittal plane (towards or away from the foot 100) and/or twisting ofthe adapter 200. For example, the links can be made of carbon fiber andcan include an arch as shown in FIGS. 7A and 7B to allow the ends of thelinks to move toward and away from each other. In some embodiments, oneor more links can have an adjustable length. For example, the embodimentof a linkage assembly shown in FIG. 8 includes a shifter 332 that allowsfor adjustment of the length of the link 330. The links can be adjustedvia manual, electrical, pneumatic, or any other suitable means.

Additional Features and Alternative Linkages

In some embodiments, the ankle module 300 can incorporate additionalfeatures. For example, the ankle module 300 can include a stance breakor swing break mechanism. Such a mechanism can selectively lock the foot100, adapter 200, and/or ankle module relative to each other to inhibitthe properties and functions of the particular linkage assembly or anklemodule and allow the foot 100 to function normally as it would ifcoupled to an adapter in a conventional manner. This can advantageouslyallow the ankle module and/or linkage assembly to function only duringcertain phases of the gait cycle. In some embodiments, the ankle module300 can include sensors to detect the orientation of the links. Theorientation of the links varies over the course of the gait cycle, sothe sensor data can be processed to determine the phase of the gaitcycle at a given time. This information can then be used to triggercertain actions during certain parts of the gait cycle. For example, astance break or swing break mechanism can be activated during a certainphase of the gait cycle as determined from the sensor data.

Various linkage assemblies having pivotal joints connected by a four-barlinkage have been shown and described herein. However, other linkagearrangements are also possible. For example, the foot 100 and adapter200 can be coupled via a polymer block or wedge. The stiffness and otherproperties of the polymer can be selected to achieve functions similarto those provided by the various linkage assemblies. Another alternativeis illustrated in FIG. 9. In this embodiment, a triangular link 1200 iscoupled to the foot member 1110 at a hinge 1310 and functions as anadapter and linkage assembly simultaneously. The triangular link 1200can be a single component or a three-bar linkage assembly. Integratedadapter linkage assemblies can have other shapes, arrangements, andorientations as well.

In some embodiments, for example as shown in FIG. 10A, the foot member2110 itself is shaped to function as a link to the adapter 2200. Aproximal attachment portion 2112 of the foot member 2110 can be coupledto another portion of the foot member 2110 via a connector 2310. Thefoot member 2110 can be made of carbon fiber or another material capableof storing and releasing energy and allowing for movement between theportion of the foot coupled to the adapter 2200 and the portion of thefoot coupled to the connector 2310.

In some embodiments, for example, as shown in the schematics of FIGS.10B and 10C, portions of both the foot member 2110 and heel member 2120form the linkage assembly. In the illustrated embodiment, the heelmember 2120 extends through an opening in the foot member 2110. The foot2110 and heel 2120 members can be coupled via a hinge or fixed joint2117 where the heel member 2120 extends through the foot member 2110.The hinge or joint 2117 can help adjust the degree to which loading andunloading of the foot member 2110 influences the loading/unloading andfunction of the heel 2120. The foot member 2110 can include a hinge 2118to allow a portion of the foot member 2110 to function as a link, andthe portion of the heel member 2120 functioning as a link can be coupledto the foot member 2110 via a hinge or joint 2116. Embodiments in whichone or more bar-type links are replaced by portions of the foot memberand/or heel member acting as links to the adapter can advantageously belighter weight due to the removal of one or more bar-type links. Suchembodiments also have fewer small parts and few components in general,which in some embodiments can help make the foot more robust as thereare fewer components that may potentially fail.

FIG. 11 illustrates another alternative embodiment of a linkagearrangement incorporating carbon fiber or similar links 3330, 3340. Inthis embodiment, the links 3330, 3340 extend between the adapter 3200and an attachment location 3320 at or near a proximal end of the footmember 3110. FIG. 12 illustrates an embodiment in which the adapter 4200includes a rotating hinge joint 4310. This feature can allow foradditional rotation and/or translation of the foot relative to theadapter and/or allow for ease of heel height adjustment. In someembodiments, one or more of the links can be bent, angular, arcuate, orotherwise non-linear, for example, bottom link 5340 shown in FIG. 13.Such non-linear links influence the progression of the instantaneouscenter of rotation of the foot during ambulation, which in turninfluences the motion of the foot about the pyramid during ambulation.

Support Springs

In some embodiments, the prosthetic foot assembly also includes asupport spring 400 coupled to the adapter and foot to limit the range ofmotion of the adapter and ankle in use and to provide improved energystorage and return. The adapter's range of motion depends at least inpart on the stiffness of the support spring, which in turn depends atleast in part on the position of the instantaneous center of rotation ofthe foot relative to the spring. For example, if the center of rotation10 is located above a connection point 410 where the spring 400 iscoupled to the foot member 110 as shown in FIG. 14A, the arc of thefoot's travel path is to the left and right of the spring 400 and thespring 400 experiences little compression and/or extension. However, ifthe center of rotation 10 is more to the side of or perpendicular to thespring 400 as shown in FIG. 14B, the arc through which the foot travelsis more aligned with the spring 400 and the spring 400 experiencesgreater compression and/or extension.

The support spring can be provided in various configurations to providedifferent functions and advantages. For example, the invertedorientation of the support spring 400 illustrated in FIG. 1Aadvantageously allows the adapter to be moved closer to the foot plateand allows the prosthetic foot to more easily fit within a cosmesiscover 500 as shown in FIGS. 1B and 1C compared to a support spring 400having an orientation similar to that shown in the embodiments of, forexample, FIGS. 4A-4D, the center embodiment of 4F, and the middleembodiment of 4H. As shown in FIG. 2K, the support spring 400 includesan aperture 430. To assemble the prosthetic foot with the support spring400, the aperture 430 is aligned with an aperture 230 in the adapter 200and coupled to the adapter 200 via a pin 350 and associated componentsas described herein. As shown in FIG. 2L, foam 420 can couple thesupport spring 400 to the foot member 110. In some embodiments, theprosthetic foot can also include a secondary support spring, forexample, secondary support spring 362 shown in the example embodiment100C of FIG. 4C. The secondary support spring 362 can help inhibitexcessive motion of the adapter during use. As shown, a distal end ofthe secondary support spring 362 can be coupled to the foot member, forexample, via bolts, fasteners, an adhesive, or any other appropriatemeans, and a proximal end of the secondary support spring 362 can befree, or unattached, and suspended beneath the adapter.

FIGS. 19A and 19B illustrate a schematic of one embodiment of aprosthetic foot assembly that provides beneficial features. In theillustration embodiment, the adapter 200 can have a length or height Hof about 35 mm-36 mm, the top links 330 can have a length of about 30mm-31 mm, and the bottom links 340 can have a length of about 46 mm-47mm. Angle 1 can be about 90°, angle 2 can be about 30°, and angle 3 canbe about 5°. This particular arrangement can allow for rotation of thefoot 100 about the adapter 200 of up to about 15° and a verticaldisplacement of up to about 13 mm. FIG. 19C illustrates how a change inthe center of rotation of the foot due to progression through the gaitcycle affects the compression of the support spring 400. The center ofrotation begins at position CoR1 and the spring 400 compresses along arc1. As the foot progresses through the gait cycle, the center of rotationshifts to position CoR2, and the spring 400 compresses along arc 2. Arc2 results in less compression of the spring 400. Of course, thesedimensions and angles are exemplary dimensions and angles for oneembodiment, and other configurations, dimensions, and angles are alsopossible.

In some embodiments, torsion bars, torsion springs, compression springs,actuated springs, elastic elements, and/or other structures can be usedas alternatives to a leaf spring to provide the functions of the supportspring. In the example embodiment shown in FIGS. 15A and 15B, theadapter 6200 includes a torsion bar 600 that provides for energy storageand return. In the illustrated embodiment, the proximal portion of thefoot member 6110 forms the top link 6330 and is coupled to the adapter6200. The foot member 6110 can include a hinge 6118 to allow a portionof the foot member 6110 to function as the top link. In someembodiments, the hinge 6118 is in line with or centered in the footmember 6110. For example, the hinge 6118 can be formed as a pivot point,for example as shown in the example embodiment of FIG. 17A and discussedbelow, or with interlocking members that form a hinge, for example, asshown in the example embodiment of FIG. 17B and discussed below. In someembodiments, the hinge 6118 can be formed as one or more grooves thatextend partially through a thickness of the foot member 6110 from eithera top or a bottom surface of the foot member 6110 and/or one or moreapertures in the foot member. Additional information regarding groovesand/or apertures that can act as hinges can be found in U.S. PatentPublication No. 2011/0208323, the entirety of which is herebyincorporated by reference herein and should be considered a part of thisspecification. Other types of hinges are also possible. The bottom link6340 is coupled to the foot member 6110 via a hinge or joint 6116. Asshown, the torsion bar 600 can be positioned at the joint 6310 where thebottom link 6340 is coupled to the adapter 6200. In some embodiments,the torsion bar 600 is designed to be able to withstand twisting of upto 10° and a moment of up to 450 Nm in use. In some embodiments, thetorsion bar 600 can be made of a glass fiber, though other suitablematerials can be used. Whereas a support spring generally limits thevertical displacement of the adapter during ambulation, the torsion bar600 functions by limiting the angular range of the links duringambulation.

In some embodiments, the support spring can be shaped to form part ofthe linkage assembly. For example, in the embodiment shown in FIGS. 16Aand 16B, the proximal portion of the foot member 7110 extends to theadapter 7200 to form the top link 7330, and a proximal portion of thesupport spring 7400 extends to the adapter 7200 to form the bottom link7340. The foot member 7110 and support spring 7400 can include hingepoints 7118, 7418 to allow portions of the foot member 7110 and supportspring 7400 to function as links. Hinge points 7118, 7418 can includepivot points and/or interlocking members within the foot member 7110and/or support spring 7400 and/or grooves extending partially through athickness of the foot member 7110 and/or support spring 7400, forexample, as discussed above with respect to FIG. 16B and below withrespect to FIGS. 17A and 17B. In some embodiments, the support spring7400 is coupled to the foot member 7110 at a hinge or joint 7412. Thisembodiment can also allow for a more robust as there are no separatelinks and fewer components that may fail.

Additional Features and Functions

In some embodiments, the prosthetic foot assembly can include additionalfeatures to provide functions such as toe clearance and/or heel heightadjustment. FIG. 17A illustrates an example embodiment of one mechanismfor providing toe clearance during swing phase. The mechanism includes awedge 702, spring 704, hinge 706 in the foot member 110, and wire 708.The hinge 706 creates a toe portion distal to the hinge 706 that ismoveable relative to the rest of the foot member 110. When the foot isunloaded, the spring 704 pulls the wedge 702 against the toe portion,holding the toe portion in a lifted configuration and providing forimproved toe clearance during swing. The wire 708 is coupled to the linkassembly at one end and the wedge 702 at the other end. When the linkassembly is loaded, the wire 708 is pulled toward the link assembly,thereby pulling the wedge away from the toe portion, as shown in thedetail view of FIG. 17A, and allowing the foot member 110 to resume itsnatural shape. FIG. 17B illustrates an example embodiment of anothermechanism for providing toe clearance during swing. As shown, a toeportion 115 is connected to the rest of the foot member 110 via a hinge1706. Flexible bumpers 1702 are disposed in the hinge 1706 between thetoe portion 115 and foot member 110. When the foot is unloaded, thebumpers 1702 cause the toe portion 115 to be lifted at an angle relativeto the foot member 110.

In some embodiments, the adapter 200 allows for adjustment of the heelheight and/or leg length. FIG. 18A illustrates an example embodiment ofa hydraulic system including two pin fixtures 802 and a motion rail 804.One pin fixture 802 can be moved up and down in the motion rail 804 viaadjuster 806 to adjust the heel height. Both pin fixtures 802 can bemoved in the motion rail 804 via adjuster 808 to adjust the leg length.FIG. 18B illustrates an example embodiment of a system for adjustingheel height and/or leg length using screws rather than a hydraulicmechanism. The heel height screw 812 moves one pin fixture to adjust theheel height, and the leg length screw 810 moves both pin fixtures toadjust the leg length.

Linkage Assembly for Knee Flexion

In some embodiments, a prosthetic foot includes a linkage assemblydesigned to simulate near-natural knee flexion, for example, early kneeflexion during the stance phase of the gait cycle. The linkage assemblycan advantageously help compensate for partial natural knee functionthat may be lost as a result of trans-tibial amputation, particularlywhen the user has a short residual limb or the residual limb isotherwise not able to withstand high moment loads. Natural knee flexionin early stance varies depending on an individual's walking style, age,and other factors; however, a natural knee often flexes by about 5° toabout 15° in early stance. A trans-tibial amputee typically flexes hisor her knee less than an able-bodied person, and in some cases, anamputee's knee may not flex at all if kept in a hyperextended statethroughout stance. Normal early stance knee flexion provides for a quickand efficient anterior transition of the person's center of mass, andloss of this function in amputees can result in high loads and/or areduced step length.

A prosthetic foot according to some embodiments of the presentdisclosure includes a linkage assembly 800 positioned between a footmodule and an ankle module that is configured to be attached to a pylon,for example as shown in FIG. 20. The links are arranged so as to buckleforward and provide a rearward angulation of the foot during earlystance as shown in FIG. 21A to simulate natural knee flexion. In someembodiments, the foot includes a spring element designed to return thepylon to a neutral orientation so that there is substantially noangulation in the prosthesis during full stance, for example, as shownin FIG. 21B.

The linkage assembly for early stance knee flexion can also be used incombination with a prosthetic knee for trans-femoral amputees. Thiscombination can also be beneficial as many prosthetic knees lack theability to dynamically flex in early stance on their own. In someembodiments, the foot and linkage assembly can be designed to guiderotational or other movements during the gait cycle. In someembodiments, the foot and/or linkage assembly include spring and/orother dampening elements (e.g., hydraulic, friction, or othermechanisms) to help control the motion of the prosthesis.

Although this disclosure has been described in the context of certainembodiments and examples, it will be understood by those skilled in theart that the disclosure extends beyond the specifically disclosedembodiments to other alternative embodiments and/or uses and obviousmodifications and equivalents thereof. In addition, while severalvariations of the embodiments of the disclosure have been shown anddescribed in detail, other modifications, which are within the scope ofthis disclosure, will be readily apparent to those of skill in the art.It is also contemplated that various combinations or sub-combinations ofthe specific features and aspects of the embodiments may be made andstill fall within the scope of the disclosure. It should be understoodthat various features and aspects of the disclosed embodiments can becombined with, or substituted for, one another in order to form varyingmodes of the embodiments of the disclosure. Thus, it is intended thatthe scope of the disclosure herein should not be limited by theparticular embodiments described above.

What is claimed is:
 1. A prosthetic foot assembly, comprising: anadapter configured to couple to a socket or pylon; a foot member havinga proximal portion that couples to the adapter, a distal portion thatextends to a distal toe of the foot member and an intermediate portionthat extends between and interconnects the distal portion to theproximal portion, the proximal portion curving upward and forward fromthe intermediate portion when the prosthetic foot is in a neutralstanding position, the distal portion curving downward and forward fromthe intermediate portion when the prosthetic foot is in the neutralstanding position, the proximal portion of the foot member including afirst link that extends to a first end of the foot member and that ispivotally coupled to the adapter at a first pivot location of theadapter; and a support spring, a proximal portion of the support springforming a second link pivotally attached to the adapter at a secondpivot location of the adapter that is different than the first pivotlocation, the second link disposed below and spaced apart from the firstlink when the prosthetic foot is in a neutral standing position, whereinthe first link extends between a hinge on the foot member and the firstpivot location of the adapter and the second link extends between thesecond pivot location of the adapter and a second hinge on the supportspring, wherein the adapter is disposed in front of and spaced apartfrom the intermediate portion of the foot member, the adapter configuredto one or both of translate and pivot relative to the intermediateportion of the foot member.
 2. The prosthetic foot assembly of claim 1,wherein the second link is configured to provide for energy storage andreturn.
 3. The prosthetic foot assembly of claim 2, wherein a portion ofthe foot member is spaced below and forward of the second link.
 4. Theprosthetic foot assembly of claim 2, wherein the second link comprises atorsion bar.
 5. The prosthetic foot assembly of claim 1, wherein thefirst hinge comprises at least one groove extending partially through athickness of the foot member from a surface of the foot member.
 6. Theprosthetic foot assembly of claim 1, wherein the support springcomprises the proximal portion coupled to the adapter, a distal portionand an intermediate portion that extends between and interconnects thedistal portion to the proximal portion of the support spring, theproximal portion of the support spring curving upward and forward fromthe intermediate portion of the support spring when the prosthetic footis in a neutral standing position, the distal portion of the supportspring curving downward and forward from the intermediate portion of thesupport spring when the prosthetic foot is in the neutral standingposition.
 7. The prosthetic foot assembly of claim 6, wherein the distalportion of the support spring is disposed above the distal portion ofthe foot member and the intermediate portion of the support spring isdisposed in front of the intermediate portion of the foot member.
 8. Theprosthetic foot assembly of claim 1, further comprising a heel memberdisposed below the foot member and extending from a forward end of theheel member rearwardly to a free heel end.
 9. The prosthetic footassembly of claim 1, wherein the foot member comprises a split extendingfrom the distal toe end of the foot member toward the intermediateportion of the foot member.
 10. A prosthetic foot assembly, comprising:an adapter configured to couple to a socket or pylon; a foot memberhaving a proximal portion that couples to the adapter, a distal portionthat extends to a distal toe of the foot member and an intermediateportion that extends between and interconnects the distal portion to theproximal portion, the proximal portion curving upward and forward fromthe intermediate portion when the prosthetic foot is in a neutralstanding position, the distal portion curving downward and forward fromthe intermediate portion when the prosthetic foot is in the neutralstanding position, the proximal portion of the foot member including afirst link that extends between a first hinge on the proximal portion ofthe foot member and a first end of the foot member and that is pivotallycoupled to the adapter at a first pivot location; and a support springhaving a proximal portion coupled to the adapter, a distal portion andan intermediate portion that extends between and interconnects thedistal portion to the proximal portion of the support spring, theproximal portion of the support spring curving upward and forward fromthe intermediate portion of the support spring when the prosthetic footis in a neutral standing position, the distal portion of the supportspring curving downward and forward from the intermediate portion of thesupport spring when the prosthetic foot is in the neutral standingposition, the proximal portion of the support spring being pivotallycoupled to the adapter at a second pivot location of the adapter that isdifferent than the first pivot location, the intermediate portion of thesupport spring disposed in front of the intermediate portion of the footmember, wherein the adapter is configured to one or both of translateand pivot relative to the intermediate portions of the foot member andthe support spring.
 11. The prosthetic foot assembly of claim 10,wherein the first pivot location is above the second pivot location. 12.The prosthetic foot assembly of claim 10, further comprising a secondhinge on the proximal portion of the support spring.
 13. The prostheticfoot assembly of claim 12, wherein the first hinge comprises at leastone groove extending partially through a thickness of the foot memberfrom a surface of the foot member and the second hinge comprises atleast one groove extending partially through a thickness of the supportspring from a surface of the support spring.
 14. The prosthetic footassembly of claim 10, further comprising a heel member disposed belowthe foot member and extending from a forward end of the heel memberrearwardly to a free heel end.
 15. A prosthetic foot assembly,comprising: an adapter configured to couple to a socket or pylon; a footmember having a proximal portion that couples to the adapter, a distalportion that extends to a distal toe of the foot member and anintermediate portion that extends between and interconnects the distalportion to the proximal portion, the proximal portion curving upward andforward from the intermediate portion when the prosthetic foot is in aneutral standing position, the distal portion curving downward andforward from the intermediate portion when the prosthetic foot is in theneutral standing position, the proximal portion of the foot member beingpivotally coupled to the adapter at a first pivot location; a supportspring having a proximal portion coupled to the adapter, a distalportion and an intermediate portion that extends between andinterconnects the distal portion to the proximal portion of the supportspring, the proximal portion of the support spring curving upward andforward from the intermediate portion of the support spring when theprosthetic foot is in a neutral standing position, the distal portion ofthe support spring curving downward and forward from the intermediateportion of the support spring when the prosthetic foot is in the neutralstanding position, the proximal portion of the support spring beingpivotally coupled to the adapter at a second pivot location of theadapter that is different than the first pivot location, wherein whenthe prosthetic foot is in a neutral standing position, the distalportion of the support spring is disposed above the distal portion ofthe foot member and the intermediate portion of the support spring isdisposed in front of the intermediate portion of the foot member; and aheel member that extends from a forward end of the heel memberrearwardly to a free heel end, the heel member disposed below the footmember; wherein the adapter is configured to one or both of translateand pivot relative to the intermediate portions of the foot member andthe support spring.